Indd CS4- Setting a Keyboard Shortcut "Set" with UI scripting

In my script below, the buttons are being pressed and the resulting “Set” is on my desired result. The dialog then closes as it should. However, when I reopen “Edit > Keyboard Shortcuts” the set chosen did not stick? Can anybody shed some insight as to why this might be. The code is very simple.

Thanks,
-Jeff

tell application "System Events"
	tell application process "Adobe InDesign CS4"
		set frontmost to true
		tell menu bar 1
			tell menu bar item "Edit"
				tell menu 1
					click menu item "Keyboard Shortcuts..."
				end tell
			end tell
		end tell
		repeat with i from 1 to count of pop up buttons of window 1
			set presetValue to get value of pop up button i of window 1 as string
			if presetValue is not "Default" and presetValue is not "Application Menu" then
				set myButton to i
				exit repeat
			end if
		end repeat
		
		click pop up button i of window 1 --open menu "Sets"
		
		--Move up the list to make sure it's on [Default]
		keystroke (ASCII character 30) -- up arrow key
		delay 0.1
		keystroke (ASCII character 30) -- up arrow key
		delay 0.1
		keystroke (ASCII character 30) -- up arrow key
		delay 0.1
		keystroke (ASCII character 30) -- up arrow key
		delay 0.1
		keystroke (ASCII character 30) -- up arrow key
		delay 0.1
		keystroke (ASCII character 30) -- up arrow key
		delay 0.1
		
		--Click on "[Default]" to temporarily set it
		keystroke (ASCII character 3) -- enter key
		delay 0.1
		
		repeat with i from 1 to count of pop up buttons of window 1
			set presetValue to get value of pop up button i of window 1 as string
			if presetValue is not "Default" and presetValue is not "Application Menu" then
				set myButton to i
				exit repeat
			end if
		end repeat
		
		click pop up button i of window 1 --open menu "Sets"
		
		
		--Go down 5 times to ensure it's now on the  Graphics key set.
		keystroke (ASCII character 31) -- down arrow key
		delay 0.1
		keystroke (ASCII character 31) -- down arrow key
		delay 0.1
		keystroke (ASCII character 31) -- down arrow key
		delay 0.1
		keystroke (ASCII character 31) -- down arrow key
		delay 0.1
		keystroke (ASCII character 31) -- down arrow key
		delay 0.1
		keystroke (ASCII character 31) -- down arrow key
		delay 0.1
		
		--Click Enter to set "Graphics" which should be the last item
		keystroke (ASCII character 3) -- enter key
		
		--Close the dialog
		keystroke (ASCII character 13) -- enter key
		
	end tell
end tell